A pressure regulator of this type is known, in which the first valve element is constituted by a head mounted at the lower end of a relatively long tubular rod which, at its upper end, is formed with a seat surface for the second valve element which is also in the shape of a valve head and which is subjected from above to the proportional setting force. The second valve element is in the deaeration zone which, in this pressure regulator, has to be necessarily effected upwardly, toward the correction member. The coupling for the secondary pressure is at the lower end of the valve box and is disposed coaxially with respect to the two valve elements. The coupling for the primary pressure is on the axial length between the couplings for the secondary pressure and for the deaeration, and reaches a toroidal chamber. The disadvantage of this known pressure regulator is that it is only usable in the case of nominal passage sections which are not over 6 mm. In this case, the magnitude of the setting force is dependent on the nominal passage section. The larger the nominal passage section, the greater the setting force has to be. The other disadvantage consists in the fact that the deaeration section which is defined by the tubular passage section in the rod is clearly less than the deaeration section. If one uses for example a proportional magnet, proportional magnets of large dimensions which are heavy and relatively costly have to be used in this known pressure regulator.
The object of the invention is a pressure regulator of the type defined in the foregoing, which allows using only reduced setting forces for high pressures and large mid pressure flow rate, and which is adapted in all cases to large nominal passage sections, which may reach for example 20 mm.
According to the invention, this object is reached by using a pressure regulator of the type initially defined, due to the fact that the second valve element includes in the middle of its end which is turned toward the seat surface of the first valve element a valve seat made of a cup, which allows the second valve element to be brought in an engagement which is substantially linear with the seat surface of the first surface element, and that the outer diameter of the cup of the second valve element corresponds to the inner diameter of the valve box cup.
Due to its structure, the pressure regulator according to the invention allows treating high pressures and large flow rates while requiring setting forces which are not very large. When for example the proportional setting force is obtained by means of proportional magnets, the latter can be, due to the invention, extremely small, light in weight, low cost and compact. The further advantage is that in the pressure regulator according to the invention the setting force necessary in each case is completely independent of the nominal passage section provided for the valve. The setting force depends only on the differential pressure surface of the second valve element. This surface may be modified and chosen without difficulty in order to adapt it to circumstances. Another advantage consists in that the pressure regulator also allows a deaeration in a direction which is opposite to that of the correction member, for example of the proportional magnets. Therefore, it becomes possible to place the correction member, notably the proportional magnets, far from the mid-pressure which flows through the pressure regulator and, consequently, to avoid subjecting them to the action of this medium. This is particularly advantageous when one uses aggressive mediums. Another advantage consists in that the deaeration section is exactly the same as the ventilation section.
Other features and advantages will become more apparent from the hereafter description.